Voltage-balanced serial iLED pixel and display

Abstract

A multi-color inorganic light-emitting diode (iLED) display includes a display substrate with a common voltage signal and a common ground signal and a plurality of multi-color pixels. In certain embodiments, each multi-color pixel includes a first color sub-pixel including two or more first iLEDs, a second color sub-pixel including one or more second iLEDs, and a third color sub-pixel including one or more third iLEDs. The two or more first iLEDs are serially connected between the common voltage signal and the common ground signal, the one or more second iLEDs are serially connected between the common voltage signal and the common ground signal, and the one or more third iLEDs are serially connected between the common voltage signal and the common ground signal.

What is claimed: 
     
       1. A multi-color inorganic light-emitting diode (iLED) pixel, comprising:
 a common voltage signal and a common ground signal; 
 a first color sub-pixel comprising two or more first iLEDs, each first iLED emitting a first color of light when provided with electrical power at a first voltage, the two or more first iLEDs serially connected between the common voltage signal and the common ground signal; 
 a second color sub-pixel comprising one or more second iLEDs, each second iLED emitting a second color of light different from the first color when provided with electrical power at a second voltage different from the first voltage, the one or more second iLEDs serially connected between the common voltage signal and the common ground signal; 
 a third color sub-pixel comprising one or more third iLEDs each emitting a third color of light different from the first and second colors of light when provided with electrical power at a third voltage different from the first or second voltage, the one or more third iLEDs serially connected between the common voltage signal and the common ground signal; and 
 a pixel controller that provides a first control signal for controlling the one or more first iLEDs to emit light and a second control signal for controlling the one or more second iLEDs to emit light, 
 wherein the number of first iLEDs is different from the number of second iLEDs and the number of second iLEDs is the same as the number of third iLEDs, 
 wherein a ratio of a controlling attribute of the first control signal to a controlling attribute of the second control signal is dependent on a ratio of the number of first iLEDs to the number of second iLEDs, and 
 wherein at least one iLED of the first color sub-pixel, the second color sub-pixel, or the third color sub-pixel has a width from 2 to 5 μm, 5 to 10 μm, 10 to 20 μm, or 20 to 50 μm, has a length from 2 to 5 μm, 5 to 10 μm, 10 to 20 μm, or 20 to 50 μm, or has a height from 2 to 5 μm, 4 to 10 μm, 10 to 20 μm, or 20 to 50 μm. 
 
     
     
       2. The multi-color inorganic light-emitting diode (iLED) pixel of  claim 1 , wherein the first color is red and the first iLED is a red iLED that emits red light, the second color is green and the second iLED is a green iLED that emits green light, and the third color is blue and the third iLED is a blue iLED that emits blue light. 
     
     
       3. The multi-color inorganic light-emitting diode (iLED) pixel of  claim 1 , comprising two serially connected red iLEDs, one green iLED, and one blue iLED. 
     
     
       4. The multi-color inorganic light-emitting diode (iLED) pixel of  claim 1 , comprising three serially connected red iLEDs, two serially connected green iLEDs, and two serially-connected blue iLEDs. 
     
     
       5. A method of making a multi-color inorganic light-emitting diode (iLED) pixel, comprising:
 providing a display substrate having a common voltage signal and a common ground signal on the display substrate; 
 providing a first color sub-pixel comprising two or more first iLEDs on or over the display substrate, each first iLED emitting a first color of light when provided with electrical power at a first voltage, the two or more first iLEDs serially connected between the common voltage signal and the common ground signal; and 
 providing a second color sub-pixel comprising one or more second iLEDs on or over the display substrate, each second iLED emitting a second color of light different from the first color when provided with electrical power at a second voltage different from the first voltage, the one or more second iLEDs serially connected between the common voltage signal and the common ground signal; 
 providing a third color sub-pixel comprising one or more third iLEDs on or over the display substrate, each third iLED emitting a third color of light different from the first and second colors of light when provided with electrical power at a third voltage different from the first or second voltage, the one or more third iLEDs serially connected between the common voltage signal and the common ground signal; and 
 providing a pixel controller that provides a first control signal for controlling the one or more first iLEDs to emit light and a second control signal for controlling the one or more second iLEDs to emit light, 
 wherein the number of first iLEDs is different from the number of second iLEDs and the number of second iLEDs is the same as the number of third iLEDs, 
 wherein a ratio of a controlling attribute of the first control signal to a controlling attribute of the second control signal is dependent on a ratio of the number of first iLEDs to the number of second iLEDs, and 
 wherein at least one iLED of the first color sub-pixel, the second color sub-pixel, or the third color sub-pixel has a width from 2 to 5 μm, 5 to 10 μm, 10 to 20 μm, or 20 to 50 μm, has a length from 2 to 5 μm, 5 to 10 μm, 10 to 20 μm, or 20 to 50 μm, or has a height from 2 to 5 μm, 4 to 10 μm, 10 to 20 μm, or 20 to 50 μm. 
 
     
     
       6. The method of  claim 5 , comprising providing a plurality of pixels on the display substrate. 
     
     
       7. The method of  claim 5 , comprising micro-transfer printing the first iLEDs from a first source substrate to the display substrate and micro-transfer printing the second iLED(s) from a second source substrate to the display substrate. 
     
     
       8. The method of  claim 5 , comprising providing an intermediate substrate, micro-transfer printing the first iLEDs from a first source substrate to the intermediate substrate and micro-transfer printing the second iLED(s) from a second source substrate to the intermediate substrate to form a pixel. 
     
     
       9. The method of  claim 8 , comprising providing a common voltage signal and a common ground signal on the intermediate substrate, serially connecting the first iLEDs between the common voltage signal and the common ground signal, and serially connecting the one or more second iLEDs between the common voltage signal and the common ground signal. 
     
     
       10. The method of  claim 8 , comprising micro-transfer printing the pixel from the intermediate substrate to the display substrate. 
     
     
       11. The method of  claim 8 , comprising providing a pixel controller that provides control signals to control the first and second iLEDs. 
     
     
       12. A multi-color inorganic light-emitting diode (iLED) display, comprising:
 a display substrate; 
 a common voltage signal and a common ground signal disposed on the display substrate; and 
 a plurality of multi-color iLED pixels disposed in an array in, on, or over the display substrate, each multi-color pixel comprising:
 a first color sub-pixel comprising two or more first iLEDs, each first iLED emitting a first color of light when provided with electrical power at a first voltage, the two or more first iLEDs serially connected between the common voltage signal and the common ground signal; 
 a second color sub-pixel comprising one or more second iLEDs, each second iLED emitting a second color of light different from the first color when provided with electrical power at a second voltage different from the first voltage, the one or more second iLEDs serially connected between the common voltage signal and the common ground signal; 
 a third color sub-pixel comprising one or more third iLEDs, each third iLED emitting a third color of light different from the first and second colors when provided with electrical power at a third voltage different from the first voltage or the second voltage, the one or more third iLEDs serially connected between the common voltage signal and the common ground signal; and 
 a pixel controller that provides a first control signal for controlling the one or more first iLEDs to emit light and a second control signal for controlling the one or more second iLEDs to emit light, 
 wherein the number of first iLEDs is different from the number of second iLEDs and the number of second iLEDs is the same as the number of third iLEDs, 
 wherein a ratio of a controlling attribute of the first control signal to a controlling attribute of the second control signal is dependent on a ratio of the number of first iLEDs to the number of second iLEDs, and 
 wherein at least one iLED of the first, second, or third iLEDs has a width from 2 to 5 μm, 5 to 10 μm, 10 to 20 μm, or 20 to 50 μm, has a length from 2 to 5 μm, 5 to 10 μm, 10 to 20 μm, or 20 to 50 μm, or has a height from 2 to 5 μm, 4 to 10 μm, 10 to 20 μm, or 20 to 50 μm. 
 
 
     
     
       13. The multi-color inorganic light-emitting diode (iLED) pixel of  claim 1 , wherein any one or more of the first color sub-pixel, the second color sub-pixel, and the third color sub-pixel is a yellow sub-pixel that comprises a yellow iLED that emits yellow light. 
     
     
       14. The multi-color inorganic light-emitting diode (iLED) pixel of  claim 1 , wherein the controlling attribute is (i) a voltage, (ii) a current, or (iii) a time period at a fixed voltage and a fixed current. 
     
     
       15. The multi-color inorganic light-emitting diode (iLED) pixel of  claim 1 , comprising a display substrate, wherein the first color sub-pixel, the second color sub-pixel, the third color sub-pixel, and the pixel controller are disposed on the display substrate. 
     
     
       16. The multi-color inorganic light-emitting diode (iLED) pixel of  claim 1 , comprising a display substrate and an intermediate substrate, wherein the first color sub-pixel, the second color sub-pixel, the third color sub-pixel, and the pixel controller are disposed on the intermediate substrate and the intermediate substrate is disposed on the display substrate. 
     
     
       17. The multi-color inorganic light-emitting diode (iLED) pixel of  claim 16 , wherein the intermediate substrate comprises connection posts. 
     
     
       18. The multi-color inorganic light-emitting diode (iLED) pixel of  claim 16 , wherein the intermediate substrate comprises a fractured tether. 
     
     
       19. The multi-color inorganic light-emitting diode (iLED) pixel of  claim 1 , wherein any one or more of the first iLED, the second iLED, and the third iLED comprises connection posts. 
     
     
       20. The multi-color inorganic light-emitting diode (iLED) pixel of  claim 1 , wherein any one or more of the first iLED, the second iLED, and the third iLED comprises a fractured tether.